Publications Details
SNL API-653 In-Service Tank Inspection and Evaluation Tank ID: 981-A2-T0 (West)
Malone, Ryan; Engineering, Sandstone
An API Standard 653 In-Service inspection was completed on Tank 981-A2-T0 (West) located at the Sandia National Laboratories TAIV tank farm in Albuquerque, NM on September 22, 2015. The inspection was completed to collect data to evaluate the mechanical integrity and fitness for continued service of the tank. No indication or records of any previous inspection were identified for this tank. The inspection and engineering evaluation were completed using API-653, 5th Edition and conservative engineering practices. The tank was not removed from service, so an internal inspection could not be completed. The tank was also fully insulated. The insulation was removed in specified areas of the tank shell and tank chime to accommodate an acoustic emission scan of the tank and an ultrasonic thickness evaluation of portions of the tank. The acoustic emission scan resulted in a grade of B / I - II indicating an overall TANKPAC grade B and composite grade II indicating minor active damage with highly concentrated sources related to corrosion found in the southeast and west side section of the tank. Eight Potential Localized Damage sources were found mainly in the west side (re-test in 2 years). The tank chime could not be inspected due to the configuration of the insulation welded angle support. An ultrasonic guided bulk wave inspection was completed on the tank shell to assess the lower shell section. At the time of the inspection the limited data collected showed minimal material loss from the shell at the thickness monitoring locations, however, visual inspection and pit depth gauge measurements showed > 3/16” inch pitting and significant general external surface corrosion on the shell at the shell to floor joint. This corrosion is caused by the insulation sheeting support welded angle iron trapping moisture and dirt against the tank shell. This tank should be removed from service, internally inspected, and repaired. Ultrasonic thickness measurement locations were established on this tank and the data is included in this report. The limited data collected indicated minimal material loss at these locations, with the only noted corrosion occurring on the tank shell to floor joint as noted above. An API-653 Annex B Evaluation of Tank Bottom Settlement was completed and the results are included in this report. No significant settlement issues were identified.